Cardiorespiratory Physiology Flashcards
What does cardiorespiratory physiology refer to
The transport and utilisation of oxygen
Where does the increased oxygen demand during exercise come from
Increased interaction between the myosin head and actin during muscle contraction which requires energy from ATP
What are the 3 methods of resynthesising ATP
Phosphagen system, glycolytic system and oxidative phosphorylation
Which method resynthesises the most ATP
Oxidative phosphorylation
What is the creatine kinase reaction
Phosphocreatine splits to phosphate and creatine “donating” it’s phosphate to ADP to form ATP
How does glycolysis generate ATP
Glucose or glycogen is broken down, generating ATP
How does oxidative phosphorylation generate ATP
Produces ATP following the breakdown of fat, carbohydrates and protein via multiple steps
Which methods of resynthesising ATP are aerobic and anaerobic
Anaerobic- creatine kinase and glycolysis
Aerobic- oxidative phosphorylation
Which method of resynthesising ATP is more sustainable and why
Oxidative phosphorylation as there are limited phosphocreatine stores and high rates of glycolysis are inhibited by acidosis
Which methods of resynthesising ATP is fastest and which is slowest
Fastest- creatine kinase
Slowest- oxidative phosphorylation
What would be the predominant energy system during a marathon, 5 second sprint and 15 second sprint
5 second- CK
15 second- glycolysis
Marathon- Oxidative phosphorylation
What is the oxygen cascade
The journey of oxygen from the atmosphere to the mitochondria
What happens to the partial pressure of oxygen as it moves down the cascade from the atmosphere to the mitochondria and why
Reduces as utilised and oxygen moves down pressure gradient
How is oxygen delivery to the mitochondria increased during exercise
Increased ventilation (TD xBR), increased cardiac output (SV x HR) and redistribution of of blood flow to meet metabolic demand of skeletal muscles
What is arterial-venous difference
How much oxygen is in venous blood after extraction from the arteries
How is arterial-venous difference calculated
The difference between oxygen concentration of the blood in the arteries and in the veins after extraction
Why does oxygen pressure decrease in tissues during exercise
Increased metabolic demand so more used
What happens to arterial-venous difference during exercise and why
Increases as more oxygen extracted so lower concentration of oxygen left in venous blood
Why is more oxygen extracted during exercise from arterial blood
Greater gradient between blood and tissue due to increased demand and utilisation for muscle contraction
What is fick’s equation
VO2= cardiac output x arterial-venous difference
Why is the initial increase of oxygen consumption gradual when exercise onsets
As it can take time for the oxygen uptake to meet demand, resulting in an oxygen deficit, therefore anaerobic mechanism. (Creatine kinase and glycolysis) are used during this time
What is VO2max
The maximal oxygen uptake as there is a limitation in the transport and utilisation of O2 despite increasing workload
What the determinants of VO2max
Any step along the oxygen cascade could be involved (pulmonary ventilation , haemoglobin concentration, blood volume and cardiac output, peripheral blood flow/ distribution and aerobic metabolism)
Which is the believed primary factor limiting VO2 max
Cardiac output
What is the difference between a maximal and submaximal VO2max test
Maximal is the gold standard, lab based test that directly determines VO2 max, submaximal estimates VO2 max by using a predetermined endpoint so may be more suited to injured or vulnerable populations as fewer risks
What are the external factors affecting VO2 max
Mode of exercise, state of training, sex, age, body size and composition
Why is a plateau not always seen when measuring VO2max
Relies on individual to exercise or true exhaustion
